Submarine groundwater discharge in Jiaozhou Bay was studied using a 222 Rn mass balance model. The researchers estimated groundwater discharge and nutrient fluxes using this model. They found that groundwater discharge flux varied between wet and dry seasons, with lower nutrient fluxes during the wet season compared to local rivers. However, during the dry season, nutrient fluxes from groundwater were similar to those from rivers. This study highlights the importance of understanding how groundwater contributes to nutrient transport in coastal areas.